Machine tool

ABSTRACT

This invention relates to a machine tool and, more particularly, to apparatus having a workhead operative for rotation and a tool carrying column which is slidable along and rotatable about an axis spaced from and parallel to the axis of the workhead.

[451 Jan.18, 1972 ilniiml Siaies atem Jacobson 1,858,754 5/1932Tessky.............. 1,940,404 12/1933 [54 J MACHINE TOQL Dumser.......

[72] Inventors: Alden H. Jacobson, Princeton, Mass. [73] Assignee:

....82/2 D ....82/3l X 2,372,692 4/1945 Svenson...... 2,389,019 11/1945Bazley et a1. 3,200,671

The l-leald Machine Company, Worcester, Mass.

8/1965 Porath........ 3,203,316 8/1965 Cashman et [22] Filed: June 29,1970 Primary Examiner-Leonidas Vlachos AttorneyNorman S. Blodgett [21]Appl.No.: 56,091

ABSTRACT Related US. Application Data .n.e wm m mam! a m Pm b X mmm ozmm m ekd lPb oo wa fim 38p e .m k mmm a .1 wm a nfi mm vhw 303 thCp 3 51 eUnS ii mUm n r. Oma mp w mm moe i bh sy 1 r. mm Thabw m wmw b WW a 8m 6 3 2B w 3mm 4 m I 2 u r. D. 2. A om 9 n 8 3, 0 1 7 o m N m L u e u nS n m f n o h m mm n .u a ":M LI .md C te d fin -Il 00 mhu Cd UIF 1]] 32 8 6 555 .l [[1 13 Claims, 4 Drawing Figures References Cited UNITEDSTATES PATENTS 1,056,332 l-lartnesg PATENTEU JAM 8 i922 SHEET 1 BF 4.mllllHIl" FIG. I

ALDEN H. JAc0Bs0/v INVENTOR PATENTED JAN I 8 i972 ll E E H 8 FIG. 3

PATENTED JAM 8 B72 SHEET 4 BF 4 lllf' FIG. 4

This is a continuation of application Ser. No. 710,389 filed Mar. 4,1968 and now abandoned.

BACKGROUND OF THE INVENTION One of the difficulties experienced in thedesign of machine tools is that they usually have required a very largebase and are complicated and expensive. Furthermore, they are usually sohigh in the vertical direction that it is difficult to find an operatorwho can operate them conveniently. Furthermore, it is difficult,particularly in the case of conventional boring machines, to introduceheavy workpieces into the work area. At the same time, it has alwaysbeen difficult to obtain rigidity of the machine between thetoolcarrying portion and the work-carrying portion, especially in thosecases where the workpiece is rotated and the tool is introduced to theworkpiece to generate a surface of revolution. These and otherdifficulties experienced with the prior art devices have been obviatedin a novel manner by the present invention.

It is, therefore, an outstanding object of the invention to provide amachine tool capable of extreme rigidity between the workhead and thetool carrying portion.

Another object of this invention is the provision of a machine tool towhich heavy workpieces may be introduced by use of an overhead crane.

A further object of the present invention is the provision of a machinetool for producing a surface of revolution in which the operativemechanism is relatively simple and uncomplicated and which is capable ofa long life of useful service with a minimum of maintenance.

It is another object of the instant invention to provide a machine toolin which the work area is located in a horizontal plane that is lowenough so that the operator can bend over the work area very readily.

A still further object of the invention is the provision of a machinetool for boring which is relatively inexpensive to manufacture.

It is a further object of the invention to provide a machine tool inwhich motion between the workpiece and the tool takes place without theuse of expensive straight ways which are difficult to manufacture anddifficult to maintain properly.

With these and other objects in view, as will be apparent to thoseskilled in the an, the invention resides in the combination of parts setforth in the specification and covered by the claims appended hereto.

SUMMARY OF THE INVENTION In general, this invention has to do with amachine tool having a surface on which appears a workhead mounted forrotation about an axis perpendicular to the surface. Substantiallyspaced from the workhead is a tool support in the form of a largecylindrical column. This column is slidable and rotatable, the rotationtaking place about an axis parallel to the axis of rotation of theworkhead. A motor operates through a transmission to operate a cam whichproduces the sliding motion of the tool support and to operate anothercam which operates the rotative motion of the column to present a toolin a suitable predetermined manner to the workpiece to produce a surfaceof revolution.

BRIEF DESCRIPTION OF THE DRAWINGS The character of the invention,however, may be best understood by reference to one of its structuralforms, as illustrated by the accompanying drawings, in which:

FIG. I is a perspective view of a machine tool embodying the principlesof the present invention,

FIG. 2 is a vertical sectional view of the machine tool taken on theline II-H of FIG. I,

FIG. 3 is a vertical sectional view of the apparatus taken on the lineIII-III of FIG. 2, and

FIG. 3 is a vertical view of the invention taken on the lines lV-IV ofFIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. I, whichbest shows the general features of the invention, the machine "tool,indicated generally by the reference numeral 10, is shown in use infinishing surfaces of revolution on workpieces II and 12 and theoperation is being observed by an operator 13. The machine tool isprovided with a base 14 adapted to rest on the floor and having agenerally horizontal deck or upper surface 15 which is enclosed in avertical wall 16. Extending upwardly from the upper surface 15 are twoworkheads l7 and 18 carrying chucks l9 and 21, respectively, forrotation about vertical axes. The chuck I9 carries the workpiece 12,while the chuck 21 carries the workpiece 11 for rotation about the axisof the surface of revolution which it is desired to finish.

Extending upwardly from the deck or upper surface 15 is a tool support22 in the form of a large cylindrical column. Attached to the upper endof the column are tool holders 23 and 24 carrying, respectively, cuttingtools 25 and 26 which, for the purpose of illustration, are shown assingle-point tools. Mounted on the machine on the general level of theupper surface 15 but exteriorly of the wall 16 :is an electric motor 27.An electrical control box 28 is located next to the operator I3, while ahydraulic unit 29 is mounted to one side of the machine and carries theusual pumps and reservoirs associated with the hydraulic supply of amachine tool. Mounted on the side of the machine is a motor 31 which ismounted with its axis vertical for driving the spindles associated withthe workheads 17 and 18. Extending from the side of the machine is achute 32 which, as will be shown hereinafter, receives coolant and chipsresulting from the machining operations taking place above the uppersurface 15.

Referring to FIG. 2, it can be seen. the tool support 22 is mounted in afixed hydrostatic bearing sleeve 33 which holds the cylindrical columnfirmly against angular movement about a horizontal axis but whichpermits vertical movement along the axis of the cylinder and rotativemovement about that same axis. The upper end of the tool support isprovided with a cap 34 having a Tee slot 35 which is used for theattachment of the tool holders 23 and 24. The bottom end of the toolsupport is connected through a link 36 to one end of a generallyhorizontal lever 37 mounted in its central portion in a journal 38having a horizontal axis, the other end of the lever being attachedthrough a link 39 to a slide 41.

This figure shows clearly the manner in which the workhead I7 is mountedvertically in the base 14, extends well above the upper deck or surfaceIS. The workhead is clearly provided with a vertical spindle 42 which isconnected by vee belts (not shown) to the output shaft of the spindlemotor 31, those same belts operating a similar spindle on the workhead18. This view shows particularly well the manner in which the upper deck15 is provided with an inclined surface 43 which slants downwardly tojoin the chute 32 for the accumulation and removal of chips and coolingfluid.

FIG. 3 shows the manner in which the tool support 22 is supported forvertical movement and for rotation about the axis of the cylinder. Atthe lower end, it is provided with a spider 43 having bushings 44 whichslide freely over dependent vertical posts 45. These posts are suspendedfrom a ring 46 which is mounted for rotation on the outside of the fixedbushing 33 in which the column is vertically slidable. The spider 43rests on a ring 47 which is bolted to the bottom of the bushing 33 andextends outwardly therefrom in the manner of a flange or shoulder.

The ring 46 is provided with an outwardly extending finger 48 on whichis mounted a connector 49 which, in turn, is actuated for the rotationof the ring 46 by means of a cam 51 shown in dotted form in thebackground. This figure also shows in dotted form the cam 52 whichoperates through the lever 37 to produce vertical movement of the toolsupport 22. It should be noted that the link 36 is connected to thelower end of a piston 53 slidable in a suitable vertical bore at thebottom end of the tool support 22. This is; for providing for extendedtravel of the column upwardly beyond what would normally be given it bythe cam 52.

Operative on the spider 43 is a step latch 54 which is pivotally mountedon the base normally pressed toward the spider 43 by a coil spring 55.it can be drawn away from the spider by a pneumatic cylinder 56.Fastened on the forward end of the connector 49 is an air cylinder 57which normally pushes the connector 49 (or cam follower) toward the cam51 to keep it in constant contact therewith. It is this piston undercontinuous air pressure which returns the tool support 22 back to itsoriginal position of rotation after a work cycle has been completed. Thesame cylinder may be used on occasion for extended travel of the columnfrom its normal extreme position of rotation as would be brought aboutby the highest point on the cam 51.

Referring now to FIG. 4, it can be seen that the cam motor 27 operatesthrough a belt 58 to operate a pulley 59 which, in turn, is connected toa pulley 61 which is keyed to a horizontal worm 62. This worm engagesand rotates a worm gear 63 which is keyed to a horizontal camshaft 64carrying at opposite ends the cams 51 and 52. A control box 65 carries aseries of limit switches 66 which engage various parts of the cams andtheir operative mechanism to stop cam motion during portions of thecycle and to limit the motions of the cams from time to time.

The operation of the apparatus will now be readily understood in view ofthe above discussion. During the time when the operator is loading theworkpieces 11 and 12 on the workheads l7 and 18 the column or toolsupport 22 would be raised vertically and rotated so that the toolholders 23 and 24 with their tools 25 and 26 would be rotated well awayfrom the workhead area. Once the workpieces have been locked in thechucks 19 and 21 the motor 27 is energized and it operates through theworm 62 and the worm gear 63 to move the cams 51 and 52. The cam 51operates through the cam follower or connector 49 to rotate the ring 46and, therefore, to rotate the tool support 22. This brings the tools 25and 26 into a preset position relative to the axes of the surface ofrevolution of the workpiece which is to be finished. In the generationof a cylinder, for instance, it would be the usual practice rotate thework support 22 to an angle where the distance from the axis of theworkhead and of the workpiece to the point of the tool is equal to thedesired radius of the cylinder. Then, the angularity of the column islocked in that position and the column is moved vertically only tointroduce the tool to the workpiece and to generate the cylindricalsurface. After the machining operation is over, it is a simple matter toswing the column in the opposite direction to move the tool away fromthe workpiece and then to swing the tool holder and tool even furtherangularly to remove it from a position overlying the workhead so thatworkpieces can be changed. When it is necessary to change tool holdersand tools, the cylinder 53 can be energized to produce an even longerlongitudinal rise of the column out of the base 14 and then produce anextraordinary angular motion by use of the cylinder 57 the column israised to a very high-vertical position and is rotated toward theoutside of the machine tool where the operator can have access to thetop of the column for changing the tool holders. The usual hydraulicfluid is supplied under pressure to the hydrostatic pockets formed onthe inside of the bushing 33 so that the cylindrical work support 22 ismounted in a long hydrostatic bearing which gives it extraordinarystiffness lending extreme accuracy to the machining operations despitemachine forces which would tend to bend the column. The column isextraordinarily large in diameter to prevent such bending and thebearing in which it is carried is in the manner described made verystifi so that these forces do not make themselves felt as a deflectionof the tool away from the desired surface of revolution to be machined.At the same time, in the manufacture of the machine, it can be seen thatthere is no need for the straight ways that are conventionally used insuch machine tools. Actually, it is a very simple procedure to generatea very accurate cylinder for the tool support 22 and to provide theinternal cylindrical surfaces in the bushing 33 to a very accuratedegree so that the guiding is accomplished to a high degree of accuracyat relatively low-manufacturing cost. The same benefit appears againwhen one is concerned with the maintenance of the machine too]. Thereare no straight ways to be bent, knocked, scratched, or otherwise placedin a condition where they fail to guide the tool holder in a straightgeometric line. At the same time, it is a very simple matter to changethe nature of the machining cycle by replacing the cams 51 and 52 withcams which are formed to take care of the new cycle. The wall 16 forms aprotective shield around the work area and causes cooling fluid andchips to fall down into the trough 40 and out through the chute 32. Itis clear that there is no large vertical column which is normally to befound in machine tools of this type, so that the machine has a lowsilhouette which makes it possible to use overhead cranes and similarhandling equipment to introduce heavy workpieces onto the workhead formachining. The advantage of the low silhouette, so far as producingaesthetic layouts of machines in a machine shop is well known; for onething, it permits the operator to see over the tops of the machines andgives the impression of uncrowdedness to a machine shop where machinesof this type I are used.

it is obvious that minor changes may be made in the form andconstruction of the invention without departing from the material spiritthereof. It is not, however, desired to confine the invention to theexact form herein shown and described, but it is desired to include allsuch as properly come within the scope claimed.

The invention having been thus described, what is claimed as new anddesired to secure by Letters Patent is:

l. A machine tool comprising,

a. a base,

b. two workheads mounted for rotation about spaced, parallel verticalaxes,

c. a tool support consisting of a vertical column arranged for verticalmovement and for rotation to introduce a tool vertically andhorizontally to a workpiece mountedon *each workhead, the tool supportbeing in the form of a cylindrical column of circular cross section ofrelatively large diameter,

d. a hydrostatic bearing mounted in the base in which the post isslidably and rotatably carried,

e. a first cam mounted in the housing for producing the verticalmovement of the tool support, and

f. a second cam mounted in the housing for producing the rotationalmovement of the tool support.

2. A machine tool as recited in claim I, wherein a tool is mounted onthe upper end of the column and directed in the downward direction sothat downward vertical movement of the tool support produces downwardmovement of the tool in the neighborhood of the workhead.

3. A machine tool as recited in claim 1, wherein a tool is mounted atthe upper end of the tool support and is directed downwardly so thatrotation of the tool support produces radial movement of the toolrelative to the axis of the workhead and to the axis of rotation of theworkpiece.

4. A machine tool as recited in claim 1, wherein a drive motor operatesthrough a transmission train to rotate the first cam for producingvertical movement of the tool support and wherein the same motor operatathrough the same transmission train to produce rotation of the secondcam which, in turn, causes rotative movement of the tool support.

5. A machine tool as recited in claim 1, wherein the tool support has alaterally directed arm on which are mounted a plurality of tools whichare successively brought into cutting engagement with a workpiece.

6. A machine tool as recited in claim 1, wherein the lower end of thecylindrical column is provided with an outwardly extending spider havinga plurality of bores, and wherein a ring is mounted concentrically withthe cylindrical column for rotation by the second cam and has aplurality of axially extending posts which extend slidably through thebores in the s ider.

7. A machine tool as recited in claim 6, wherein a step latch is mountedon the base for selective engagement with the spider.

8. A machine tool as recited in claim 7 wherein a pneumatic cylindercontinuously biases the ring toward engagement by the second cam.

9. A machine tool as recited in claim 1, wherein a pneumatic cylinder ismounted coaxially of the cylindrical column to permit selection of therange of travel due to the first cam.

110. A machine tool comprising a. a base,

b. a workhead mounted for rotation about a vertical axis,

0. a tool support consisting of a vertical column arranged for verticalmovement and for rotation to introduce a tool vertically andhorizontally to a workpiece mounted on the workhead, the tool supportbeing in the form of a cylindrical column of circular cross section ofrelatively large diameter, the lower end of the cylindrical column beingprovided with an outwardly extending spider having a plurality of bores,

d. a hydrostatic bearing mounted in the base in which the post isslidably and rotatably carried,

e. a first cam mounted in the housing for producing the verticalmovement of the tool support f. a second cam mounted in the housing forproducing the rotational movement of the tool support, and

g. a ring mounted concentrically with the cylindrical column forrotation by the second cam, the ring having a plurality of axiallyextending posts which extend slidably through the bores in the spider.

1111. A machine tool as recited in claim 10, wherein a step latch ismounted on the base for selective engagement with the spider.

12. A machine tool as recited in claim 10, wherein a pneumatic cylindercontinuously biases the ring toward engagement by the second cam.

13. A machine tool comprising a. a base,

b. a workhead mounted for rotation about a vertical axis,

c. a tool support consisting of a vertical column arranged for verticalmovement and for rotation to introduce a tool vertically andhorizontally to a workpiece mounted on the workhead, the tool supportbeing in the form of a cylindrical column of circular cross section ofrelatively large diameter,

. a hydrostatic bearing mounted in the base in which the post isslidably and rotatably carried,

e. a first cam mounted in the housing for producing the verticalmovement of the tool support,

f. a second cam mounted in the housing for producing the rotationalmovement of the tool support, and

g. a pneumatic cylinder is mounted coaxially of the cylindrical columnto permit selection of the range of travel due to the first cam.

=l it: =3 i l

1. A machine tool comprising, a. a base, b. two workheads mounted forrotation about spaced, parallel vertical axes, c. a tool supportconsisting of a vertical column arranged for vertical movement and forrotation to introduce a tool vertically and horizontally to a workpiecemounted on each workhead, the tool support being in the form of acylindrical column of circular cross section of relatively largediameter, d. a hydrostatic bearing mounted in the base in which the postis slidably and rotatably carried, e. a first cam mounted in the housingfor producing the vertical movement of the tool support, and f. a secondcam mounted in the housing for producing the rotational movement of thetool support.
 2. A machine tool as recited in claim 1, wherein a tool ismounted on the upper end of the column and directed in the downwarddirection so that downward vertical movement of the tool supportproduces downward movement of the tool in the neighborhood oF theworkhead.
 3. A machine tool as recited in claim 1, wherein a tool ismounted at the upper end of the tool support and is directed downwardlyso that rotation of the tool support produces radial movement of thetool relative to the axis of the workhead and to the axis of rotation ofthe workpiece.
 4. A machine tool as recited in claim 1, wherein a drivemotor operates through a transmission train to rotate the first cam forproducing vertical movement of the tool support and wherein the samemotor operates through the same transmission train to produce rotationof the second cam which, in turn, causes rotative movement of the toolsupport.
 5. A machine tool as recited in claim 1, wherein the toolsupport has a laterally directed arm on which are mounted a plurality oftools which are successively brought into cutting engagement with aworkpiece.
 6. A machine tool as recited in claim 1, wherein the lowerend of the cylindrical column is provided with an outwardly extendingspider having a plurality of bores, and wherein a ring is mountedconcentrically with the cylindrical column for rotation by the secondcam and has a plurality of axially extending posts which extend slidablythrough the bores in the spider.
 7. A machine tool as recited in claim6, wherein a step latch is mounted on the base for selective engagementwith the spider.
 8. A machine tool as recited in claim 7 wherein apneumatic cylinder continuously biases the ring toward engagement by thesecond cam.
 9. A machine tool as recited in claim 1, wherein a pneumaticcylinder is mounted coaxially of the cylindrical column to permitselection of the range of travel due to the first cam.
 10. A machinetool comprising a. a base, b. a workhead mounted for rotation about avertical axis, c. a tool support consisting of a vertical columnarranged for vertical movement and for rotation to introduce a toolvertically and horizontally to a workpiece mounted on the workhead, thetool support being in the form of a cylindrical column of circular crosssection of relatively large diameter, the lower end of the cylindricalcolumn being provided with an outwardly extending spider having aplurality of bores, d. a hydrostatic bearing mounted in the base inwhich the post is slidably and rotatably carried, e. a first cam mountedin the housing for producing the vertical movement of the tool supportf. a second cam mounted in the housing for producing the rotationalmovement of the tool support, and g. a ring mounted concentrically withthe cylindrical column for rotation by the second cam, the ring having aplurality of axially extending posts which extend slidably through thebores in the spider.
 11. A machine tool as recited in claim 10, whereina step latch is mounted on the base for selective engagement with thespider.
 12. A machine tool as recited in claim 10, wherein a pneumaticcylinder continuously biases the ring toward engagement by the secondcam.
 13. A machine tool comprising a. a base, b. a workhead mounted forrotation about a vertical axis, c. a tool support consisting of avertical column arranged for vertical movement and for rotation tointroduce a tool vertically and horizontally to a workpiece mounted onthe workhead, the tool support being in the form of a cylindrical columnof circular cross section of relatively large diameter, d. a hydrostaticbearing mounted in the base in which the post is slidably and rotatablycarried, e. a first cam mounted in the housing for producing thevertical movement of the tool support, f. a second cam mounted in thehousing for producing the rotational movement of the tool support, andg. a pneumatic cylinder is mounted coaxially of the cylindrical columnto permit selection of the range of travel due to the first cam.